256016640 has 432 divisors, whose sum is σ = 978667200. Its totient is φ = 56770560.

The previous prime is 256016627. The next prime is 256016647. The reversal of 256016640 is 46610652.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 256016598 and 256016607.

It is not an unprimeable number, because it can be changed into a prime (256016647) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8828146 + ... + 8828174.

Almost surely, 2^256016640 is an apocalyptic number.

256016640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256016640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (489333600).

256016640 is an abundant number, since it is smaller than the sum of its proper divisors (722650560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256016640 is a wasteful number, since it uses less digits than its factorization.

256016640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 256016640 is about 16000.5199915503. The cubic root of 256016640 is about 634.9741779650.

The spelling of 256016640 in words is "two hundred fifty-six million, sixteen thousand, six hundred forty".